Adhesive composition components such as base polymers, tackifiers, waxes, and oils are customarily provided as separate components for formulation into hot melt adhesive (HMA) compositions. In HMA packaging applications, adhesive compositions are sought that provide a desired combination of physical properties, such as reduced set time and improved mechanical strength, including fiber tear and failure mode for broad application temperature ranges.
Exemplary base polymer compositions and methods of making polymer compositions for HMA applications that can be used for packaging applications are disclosed in U.S. Pat. Nos. 7,294,681 and 7,524,910. Various polymers described in these patents and/or produced by the methods disclosed in these patents have been sold by ExxonMobil Chemical Company as LINXAR™ polymers.
International Publication No. 2013/134038 discloses a method for producing a polymer blend having at least two different propylene-based polymers produced in parallel reactors. The multi-modal polymer blend has a Mw of about 10,000 g/mol to about 150,000 g/mol. International Publication No. WO2015/164017 filed on Mar. 24, 2015 discloses an adhesive composition having 50-95 wt % of the polymer blend disclosed in International Publication No. 2013/134038 and a tackifier having a softening point of 95-115° C., an aromaticity of 3-10 mol % aromatic protons, and a cloud point of 40-65° C.
Many different types of polymers and tackifiers are known and have been used in HMA formulations for packaging applications. Generally, adhesive formulations for these applications are prepared by combining polymer, tackifier, and wax in equal quantities. However, there remains a need for a tackified adhesive formulation that has the new base polymer combined with one or more tackifiers that is suitable for low temperature applications.